<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>box</title>
    <style>
        .box {
            width: 300px;
            height: 300px;
            background-color: gray;
            /*padding: 10px;  !*四个方向，内边距全为10px*!*/
            /*padding: 10px 20px;  !*上下内边距为10px，左右为20px*!*/
            /*padding: 10px 20px 30px 40px;  !*方向为上右下左*!*/
            padding-top: 10px;  /*上内边距*/
            padding-right: 20px;   /*右内边距*/
            padding-bottom: 10px;   /*下内边距*/
            padding-left: 20px;     /*左内边距*/
            border-left: 2px solid darkblue;
            border-bottom: 2px dotted darkcyan;
            border-right: 2px dashed darkorange;
            /*margin: 30px;*/
            margin: 10px auto;  /*左右外边距设置为自动，则该元素居中显示*/
        }
        span {
            display: block;
            width: 200px;
            height: 200px;
            background-color: antiquewhite;
        }
        .c1,.c2 {
            width: 300px;
            height: 300px;
            float: left;
        }
        .c1 {
            background-color: gray;
        }
        .c2 {
            background-color: burlywood;
        }
        .clear {
            clear: both;
        }
    </style>
</head>
<body>
<div class="c1">c1</div>
<div class="c2">c2</div>
<div class="clear"></div>
<div>
    <span>Hello World!</span>
    <span>How Are You?</span>
</div>
<div class="box">
    达内云计算
</div>
</body>
</html>